1. Field of the Invention
Intravenous catheter insertion device which protects the user from accidental needle-stick injury from the insertion needle and the patient from Teflon or Silastic embolism.
2. Prior Art
"Needle-stick" injuries, especially with the hollow-bore steel needles commonly used for withdrawing blood are now the most common cause of AIDS and serum hepatitis in health care workers who are otherwise at low risk. Such needles, once used, may contain a large number of blood cells. The U.S. Centers for Disease Control have advised workers not to manually resheath needles used for giving injections or withdrawing blood, and have urged the deposition of used needles into safe containers as soon as possible. (See MMWR June 23, 1989/Vol. 38/No. 5-6--Guidelines for prevention of transmission of Human Immunodeficiency Virus and Hepatitis V Virus to Health-Care and Public-Safety Workers).
Each kind of needle used for withdrawing blood, giving infusions into veins or giving medications under the skin presents special safety problems. For intravenous needles such as phlebotomy needles, "butterfly needles", vacutainer needles and some straight needle/syringe combinations, these problems have been addressed. In a co-pending U.S. patent application Ser. No. 07/226,134, now U.S. Pat. No. 4,932,946, the present inventor describes a hub-mounted permanently attached slit elastic sheath designed for protecting the user, as well as the patient from accidental needle stick injury. Here I describe methods for preventing needle-stick injuries from hollow bore steel needles used to insert silastic intravenous catheters, especially after such introducing needles are withdrawn from the soft hub-mounted catheters.
The use of syrettes to insert the contents of cartridges containing medications, especially penicillin, morphine or cocaine derivatives, through retractable, disposable needles has been commonly practiced since World War II. Such hinging metal holder/cartridge/retractable needle assemblies are still useful for giving shots with minimal chance for the health care workers getting "needle-stuck" after use. However, removal of the exhausted cartridges and disposable needles from reusable housing assemblies for subsequent disposal expose personnel to the danger of accidental needle stick injury from the dangerous and, possibly, HIV or HBV-contaminated hollow-bore needle tips.
In U.S. Pat. No. 4,334,536 issued 6/15/82, Pfleger described pre-filled syringes in which the means for attaching the needle assembly to the syringe, the needle cover and the activating mechanism are unitized, but breakable at specific points to expose the needle and empty the syringe. However, Pfleger provides no means for safely resheathing the needle after use.
Haber et al, U.S. Pat. No. 4,767,413 issued 8/30/88 describes a disposable dental syrette which manually retracts and safely resheaths the needle back in the housing after the cartridge contents have been injected into soft tissues. Such syrettes are considered to be user-safe with respect to needle-stick injuries, but are not suitable for giving continuous, prolonged infusions into soft tissues or into veins.
Beck, in U.S. Pat. No. 4,068,660 issued 1/17/78 describes disposable assemblies for safely inserting break-away silastic catheters via straight or curved hollow-bore steel needles into veins for the purpose of giving continuous infusions. Beck describes methods to prevent the sharp insertion needles from shearing the catheters. However, no means were described for safely resheathing the hollow-bore steel needles obliged to contain blood after proximal withdrawal from the catheter via a firmly attached wire needle guide.
In U.S. Pat. No. 4,702,735 issued 10/27/85, Luther, Snyder and Whitehouse describe an assembly consisting of a break-away needle and catheter operable by the user employing only one hand. The device included adhesive-coated taped wings to enhance in-site attachment of the silastic catheter for long term use. As in the other prior art references, no means were described for safely sheathing the broken-away steel needle after insertion of the silastic catheter; or for securing the catheter firmly to the assembly during insertion.
In U.S. Pat. No. 4,642,101 issued 2/10/87, Krolikowski and Shahnarian described a smooth bulbous tipped catheter which, after withdrawal of the inserting steel needle, leaves a blunt non-lacerating conduit for intravenous fluid. The catheter was designed with a broad base to prevent breakage, and with multiple break-away perforated tabs to provide options for suturing the hub to patient's skin. No means were described for safely resheathing the steel needle used to insert the device. Sitar, in U.S. Pat. No. 4,846,805, discloses a catheter insertion device comprising a long cylindrical collection tube having a distal conical catheter subassembly slides on the conical end to substantially cover the introducer needle. Once the introducer needle penetrates a selected vein and the catheter is advanced into the lumen of the vein, a guard member which is concentrically and slideably mounted over the collection tube is slid forward pushing the catheter off of the conical end of the introducer tube. At the end of its travel, the guard mechanically locks in place to protectively cover the entire introducer needle. Sitar's device has the disadvantage that although the intravenous catheter is prevented from rotating over the introducer needle, the catheter can inadvertently slip forward such that it may be sheared by the needle. Moreover, once the introducer needle is withdrawn from the catheter, the catheter can immediately spill venous blood over the patient.
In addition to the problem of accidental needle stick injury inherent in the prior art devices, there is an additional risk of silastic embolism to the patient. If the tip of the introducer needle is permitted to slide back inside the silastic intravenous catheter, there is a danger that the sharp tip may remove a portion of the inner wall of the catheter. The removed piece may enter the blood stream and cause embolism.
Currently, an untold number of related devices are under development. These may include concentric plastic tubes which slide back over steel needles used for one-handed insertion of hub-mounted silastic catheters (such as PROTECTIV.TM. manufactured by CRITIKON); or tubes into which the steel needles can be retracted. None of these embody means for securely anchoring the detachable silastic catheter during intravenous insertion; for varying the length of exposed steel needle beyond the tip of the silastic catheter; for preventing the embolization of cut-off silastic in the case of inaccurate insertion; or for leaving the catheter insertion needle in a safe disposable needle trap. It should be understood that the observation of "flash-back" of venous blood during needle insertion will be enhanced by usage of parts of optimal optic clarity.